The present invention relates generally to the application of coatings to aircraft engine parts. More specifically, the present invention relates to a process for spraying different thicknesses of coating onto an aircraft engine part.
Certain aircraft engine parts can require that selected areas of the part have a coating thickness that is different from other areas of the part. There are currently two different methods for inducing differential thickness patterns into a coating on an engine part.
The first method for inducing a differential thickness pattern into a coating on an engine part is to spray the coating to the thickest required dimension on the engine part and then remove portions of the coating in selected areas of the engine part by sanding or other material removal process to achieve the desired differential thickness pattern of the coating. This method has several drawbacks. One drawback is that significant amounts of coating are being sprayed onto the part only to be subsequently removed, thereby resulting in a waste of coating materials. Another drawback is that the sanding or material removal process can be a very labor intensive and costly process. Still another drawback is that the sanding or material removal process can be inexact. The inexactness of the sanding or material removal process can result in an incorrect differential thickness pattern being induced into the coating or the generation of an undesirable rough transition between the different coating thicknesses.
The second method for inducing a differential thickness pattern into a coating is to construct a shadow mask. The shadow mask is placed on the part and a series of coats of the coating material are applied to the engine part. The shadow mask is then removed and the remaining coats of the coating material are applied to the engine part to achieve the differential thickness pattern in the coating. This method also has several drawbacks. One drawback is that the construction of the shadow mask can be a very costly and labor intensive process. Another drawback is that the use of the shadow mask can be inexact. The inexactness of the shadow mask usage can result in an incorrect differential thickness pattern being induced into the coating or the generation of an undesirable rough transition between the different coating thicknesses.
Therefore, what is needed is a process for accurately spraying differential or non-uniform coating thicknesses onto an aircraft engine part in a single operation.
The present invention sets forth a method for applying a coating to an aircraft engine component in a repetitive pattern and in a manner to achieve a coating having a preselected thickness in a predetermined location of the component, such that the coating is not uniform across the part. The method utilizes an automated machine that is programmed by selecting a starting point and an end point and one or more intermediate points. The machine stores these points as learned points and applies the coating in accordance with a predetermined program, and along a predetermined path using a modified thickness at any intermediate points as newly learned points.
One embodiment of the present invention is directed to a method for spraying a coating on an aircraft engine part. The method includes providing an aircraft engine part to receive a coating and providing a robotic system comprising a controller and an end effector. The end effector being configured to spray coating material on the aircraft engine part. The controller having a motion plan and a control program to control operation of the end effector to spray a coat of coating material having a predetermined thickness onto the aircraft engine part. A profile of predetermined areas of the aircraft engine part requiring a different thickness of coating is determined and the control program is modified by integrating the profile of the aircraft engine part into the control program to generate a modified control program. The motion plan and the modified control program control the operation of the end effector to spray a coat of coating material having the predetermined thickness on only the predetermined areas of the aircraft engine part in the profile. A pass of the end effector over the aircraft engine part using the motion plan and control program is completed and an additional pass of the end effector over the aircraft engine part is completed using the motion plan and the modified control program. Finally, the steps of completing a pass of the end effector and completing an additional pass of the end effector are repeated until the desired coating has been sprayed on the aircraft engine part.
Another embodiment of the present invention is directed to a method for inducing a differential thickness pattern into a coating on an aircraft engine part. The method includes providing an aircraft engine part to receive a coating and determining the areas of the aircraft engine part requiring a thicker coating. The areas of the aircraft engine part requiring a thicker coating are correlated to points on a predetermined path traveled by a spray mechanism of an automated machine. The points on the predetermined path corresponding to the areas of the aircraft engine part requiring a thicker coating are integrated into a control program for the spray mechanism in the automated machine. The control program is used to move the spray mechanism along the predetermined path and to trigger spraying of the coating by the spray mechanism on the areas of the aircraft engine part requiring a thicker coating. A coat of the coating having a predetermined thickness is sprayed onto the aircraft engine part with the spray mechanism by activating the spray mechanism and moving the spray mechanism along the predetermined path and an additional coat of the coating is sprayed onto preselected areas of the aircraft engine part requiring a thicker coating using the control program to operate the spray mechanism. Finally, the steps of spraying a coat of the coating having a predetermined thickness onto the aircraft engine part and spraying an additional coat of the coating onto preselected areas of the aircraft engine part requiring a thicker coating are repeated until the desired differential thickness pattern has been induced on the aircraft engine part.
Still another embodiment of the present invention is directed to a method for inducing a differential thickness pattern into a coating on an aircraft engine part. The method includes providing an aircraft engine part to receive a coating and determining areas of the aircraft engine part requiring a thicker coating. Next, the areas of the aircraft engine part requiring a thicker coating are correlated to points on a predetermined path traveled by a spray mechanism of an automated machine. The points on the predetermined path corresponding to the areas of the aircraft engine part requiring a thicker coating are integrated into a control program for the spray mechanism. The control program is used to move the spray mechanism along the predetermined path and to trigger spraying of the coating by the spray mechanism. A coat of the coating having a predetermined thickness is then sprayed onto the aircraft engine part followed by the spraying of an additional coat of the coating onto preselected areas of the aircraft engine part requiring a thicker coating. Finally, the steps of spraying a coat of the coating having a predetermined thickness onto the aircraft engine part and spraying an additional coat of the coating onto preselected areas of the aircraft engine part requiring a thicker coating are repeated until the desired differential thickness pattern has been induced on the aircraft engine part.
One advantage of the present invention is that a differential thickness pattern for a coating can be sprayed onto an engine part with extreme accuracy and control.
Another advantage of the present invention is that a coating having different thicknesses can be sprayed onto an engine part quickly, economically and with less wasted coating material.
Other features and advantages of the present invention will be apparent from the following more detailed description of the preferred embodiment, taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the invention.